query: SELECT avg(LifeExpectancy) FROM country WHERE Region  =  "Central Africa"
question: What-all for countries in the region of Central Africa is the average expect life expectancy?
query_toks: SELECT avg ( LifeExpectancy ) FROM country WHERE Region = `` Central Africa ''
query_toks_no_value: select avg ( lifeexpectancy ) from country where region = value
question_toks: What-all for countries in the region of Central Africa is the average expect life expectancy?